Microorganisms, which have a large ratio of surface to volume, produce a variety of surface active agents. A wide variety of surface active agents having a molecular weight of less than about 2000 daltons is produced by microbes. Amongst these there may be mentioned substances which are surface active and which are produced by species such as Rhodococcus, Torulopsis, Pseudomonas, Corynebacterium, B. subtilis etc.
A variety of microbial surfactants which are generally mixtures of proteins and polysaccharides are produced by Acinetobacter calcoaceticus. Other surfactants are produced by Candida tropicalis, Pseudomonas aeruginosa, Phormidium J-1. None of the known surface active substances produced by bacteria, and by the above mentioned microorganisms, are effective as dispersants of finely divided materials.
Dispersing agents are specific surface active substances which are adapted to assist in the formation and in the stabilization of finely divided solids in a liquid, generally in an aqueous system. Dispersing agents are used on a wide scale in various manufacturing processes, such as the production of paper, inks, paints, pharmaceuticals, plastics, dyes, foodstuffs, ceramics, rubber, cement and the like. Dispersants are widely used in mining industries. Such dispersing agents generally exert their activity by adsorption onto the solid particles, resulting in an electric charge of these, which are subsequently surrounded by counterions, resulting in the repulsion of adjacent particles by each other, preventing flocculation and thus maintaining such finely dispersed particles in suspension.
No bacterially produced polymeric dispersing agents for finely divided minerals are known hitherto. The present invention provides novel polymeric substances which are efficient as dispersing agents in comparatively small concentrations. These can be produced in comparatively pure form by fermentation processes.